Analysis apparatus

ABSTRACT

An analysis apparatus (1) for carrying out chemical analyses is disclosed, having a base member (3) in which there is at least one channel (8, 9), and having at least one functional element (12) which is in fluid or gaseous connection with the channel. In such an apparatus, it is desirable to facilitate maintenance and increase flexibility. For that purpose, the functional element (12) is positioned on the outside of the base member (3) and is in connection with the channel (8, 9) by way of at least one interface opening (10, 11).

BACKGROUND OF THE INVENTION

The invention relates to an analysis apparatus for carrying out chemicalanalyses having a base member in which there is at least one channel,and having at least one functional element which is in fluid or gaseousconnection with the channel.

In certain chemical analyses, a chemical sample that is able to flow ismixed with at least one reagent. The reagent reacts with the sample. Aresulting reaction product, for example, a colour change, can then bedetected by a detector.

To control the route from sample to reagent, U.S. Pat. No. 5,250,263describes an analysis apparatus which essentially consists of aplurality of plates which are layered one above another in the manner ofa stack. In each plate there are channels in the form of grooves in oneof the surfaces, bores or openings which together form with a platearranged thereover longitudinally or transversely running channels orreaction chambers. Furthermore, between individual plates there areprovided membranes which can be acted on with compressed air throughseparate channels. These membranes then act as pumps. Valves whichcontrol the path of the fluids through the channels, for example,preventing a back flow, are also provided in some plates.

Such an apparatus can be of relatively compact construction, which hasthe advantageous effect that the necessary amounts of sample and reagentcan be kept relatively small. Certain problems arise in handling,however, because the functional elements, for example, the valves andthe pumps, are virtually inaccessible for maintenance. If such afunctional element is defective, it is frequently the case that theentire apparatus must be exchanged. Moreover, in an experimentalenvironment it is relatively difficult to undertake changes, forexample, in respect of the characteristics of the pumps or the valves,because to do so the apparatus has to be virtually completely destroyed.Since there are a number of channels which are formed by successivebores, it is virtually impossible on assembly to repeat the sameflow-through characteristics of these channels. Even small shifts in theindividual plates relative to one another cause irregularities in thewalls of these channels, which change the flow conditions there.Provided that only a few stages are affected, this can be tolerated. Inthe case of the described large number of superimposed plates, however,satisfactory reproducibility is very unlikely. In practice, componentscannot be exchanged.

SUMMARY OF THE INVENTION

The invention is based on the problem of providing an analysis apparatusin which maintenance is simplified and which is distinguished by amodular construction, the manufacture of which is simple and which isversatile and robust in operation.

That problem is solved in an analysis apparatus of the kind mentioned inthe introduction in that the functional element is positioned on theoutside of the base member and is in connection with the channel by wayof at least one interface opening.

In this manner the conduction paths are separated from the functionalelements from construction onwards. The conduction paths or channels (inmost cases several channels will be provided) are located in the basemember. The base member is formed from a rigid material which does notyield when subjected to the pressures prevailing in the channels andthus guarantees that the volume of the channels will be constant. Thefunctional elements, for example, pumps, valves or detectors, arelocated on the outside. They can be compared with a printed circuitboard in electronics, where the individual printed conductors areprovided on the printed circuit board whilst the electrical orelectronic components, such as transistors, resistors, capacitors and soon, are mounted on the printed circuit board and electrically connectedto the printed conductors. The connection between base member andfunctional element is effected by way of an interface opening, that is,a defined point, at which the channel or a part branching therefrom islead to the surface of the base member. An opening in the functionalelement is correspondingly matched so that transport of fluid or gasfrom the base member into the functional element or vice versa ispossible. Because the functional element is positioned externally on thebase member, it can be exchanged without difficulty. This has advantagesduring repair or maintenance. A defective part can easily be exchanged.At the experimental stage it is possible to try out different functionalelements at the same point or find out which element or what size ofelement is best suited. Construction is such that production also issimplified.

In a preferred construction, the base member comprises a stack of platescomprising at least two adjacent plates, in the area of contact of whichthe channel is formed, at least one plate having on its free surface amounting area for the functional element. The interface openings arearranged in this mounting area. At the same time, however, it ispossible to secure the functional element to the base member here, sothat coordination of the interface openings with the functional elementcan be ensured in a simple manner.

The base member preferably comprises several parts, each part having amain flow direction and the main flow directions of at least two partsdiffering from one another. In this manner, channels which run mainly inone direction can be arranged in one part whilst channels that runtransversely thereto can be arranged in another part. This facilitatesconstruction quite considerably because intersection problems arelargely avoided. Moreover, this construction has the advantage thatbetween the individual channels sufficient material can be left in thebase member for the ability of the channels to resist pressure to beincreased. In particular, in each part a plurality of channels can bearranged parallel to one another and can be combined virtually asdesired with one another by different linkages in another part. Ananalysis apparatus which can be adapted to many requirements is obtainedusing simple basic equipment.

Versatility is yet further improved in that the analysis apparatus is ofmodular construction and comprises at least one tank module, anevaluation module and a pump module. By simple exchange of one orseveral modules the analysis apparatus can be readily adapted to adesired application.

Here, the base member preferably forms the pump module. The pump orpumps that are required to set the individual fluids and gases moving inorder to mix them with one another or to bring them to a differentlocation are here arranged on the base member. The base member is inmost cases of a more mechanically stable construction that other modulesanyway, because it is used as carrier for the other modules. Thisincreased mechanical stability can then also be exploited to carry thepumps, because experience shows that the highest pressures are to beexpected in the immediate vicinity of the pumps.

Mutually-associated modules preferably lie with interfaces adjacent toone another. These interfaces represent on the one hand the fluidconnections between individual modules and provide on the other hand anopportunity to join two modules mechanically.

The tank module preferably has a mounting and a connection for at leastone tank. The reagent, a cleaning fluid or a carrier fluid can becontained in such a tank. Because the tank module has not only aconnection but also a mounting for the tank, not only is the transportof fluid from the tank to the other parts of the analysis apparatusensured, but also the mechanical fixing of the tank.

In an especially preferred construction, the connection is in the formof a quick-release coupling. Exchange of a tank, for instance when thetank is emptied, can be effected relatively quickly.

It is also preferred for the connection to comprise a tank-piercingdevice. As the tank is inserted, it is thus simultaneously opened. Thisreduces the time taken for tank change. Tank change is additionallyfacilitated in that the piercing device makes a hole in the bottom ofthe tank so that fluid is able to flow out. There is therefore no needfor an opened tank to be tilted or emptied out.

The pump module preferably comprises at least one valve. This enablesthe fluid path to be controlled in the vicinity of the pump.

The pump module preferably comprises several pumps which are arranged inseveral rows offset with respect to one another. The channels in thepump module can therefore be moved closer together because there is nolonger any requirement to leave sufficient space between the individualchannels for a pump to fit between them.

It has proved useful for the evaluation module to comprise at least onedetector. The detector can function in known manner, for example,optically, ion-selectively or electrochemically. Evaluation is thencarried out directly in the apparatus.

It is herein especially preferred for the detector to be arranged in adetector module which is connected to the evaluation module. In thismanner, the detector too can be easily exchanged, without requiringfurther parts to be exchanged. The analysis apparatus can thus bereadily adapted to different requirements.

The evaluation module preferably comprises a sample-removal channel. Thesample is therefore supplied to the evaluation module immediately. Thiskeeps the time taken to transport the sample through the apparatusshort, so that the response or reaction times can be keptcorrespondingly short.

The evaluation module advantageously has a mixing point which isconnected to the sample-removal channel by way of a pump. This pump,which, as an exception, is not arranged on the pump module, conveys thesample to the mixing point. Mixing of the sample with the reagent cantherefore be controlled relatively accurately.

A reaction channel module is preferably connected to the evaluationmodule. The reaction channel too can then be exchanged relativelyquickly. For example, reaction channels of different lengths can beused, so that even as regards the reaction channel, adaptation todifferent conditions can be achieved relatively easily.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinafter with reference to a preferredembodiment in conjunction with the drawings, in which:

FIG. 1 is a diagrammatic sectional view of an analysis apparatus and

FIG. 2 is a partial section II--II of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An analysis apparatus 1 is arranged in a housing 2. The analysisapparatus 1 has a base member 3 in the form of a stack of plates, theconstruction of which is shown in FIG. 2.

The base member 3 consists in this particular case of two plates 4, 5,one plate 4 having grooves 6, 7 in its face that contacts the otherplate 5; the grooves can be created by milling or etching or, throughthe shaping of a corresponding casting mould, as such a plate is beingcast. These grooves 6, 7 are covered by the other plate 5, thus creatingchannels 8, 9 (FIG. 1). To support the plates, they can be secured to asolid supporting plate. This is advantageous if the plates 4 and 5 aremanufactured from a relatively soft plastics material.

The other plate 5 has interface openings 10, 11 which are in connectionwith the channels 8, 9. A pump 12, in connection by way of the interfaceopenings 10, 11 with the channels 8, 9, is arranged on this plate 5. Thepump 12 is therefore positioned on the base member 3 or, moreaccurately, on the plate 5, from the outside. For that purpose amounting area 13, on which the pump 12 can be not merely positioned butalso secured, is provided on the plate 5.

As is apparent from FIG. 1, several substantially parallel channels 8,14-19 are provided in the base member 3, most channels 8, 14-19 beingassociated with a pump 12, 20-24, all of which are arranged in themounting area 13 of the base member 3. The pumps 12, 20-24 are, in anidentical manner, in connection with the channels 8, 14-19 throughinterface openings, as illustrated for pump 12 in FIG. 2.

In the embodiment illustrated, the pumps 12, 20-24 are arranged in tworows, the pumps in the two rows being offset with respect to oneanother. They are therefore arranged staggered, as it were. Theindividual channels 8, 14-19 can thus be arranged closer than would onthe whole be possible given the width of the pumps 12, 20-24.

Valves or other functional elements can be positioned on the base member3 in place of pumps, and can then be connected by way of correspondinginterface openings to the channels.

Because it is equipped with pumps, the base member 3 can also bereferred to as the pump module.

Positioned on the base member 3 in the region of its upper end is a tankdistributer 25, which adjoins the base member 3 by way of an interface26. In the interface there are again interface openings 27 in the plate5 which interface openings are in connection with corresponding openings28 in the tank distributer 25. A channel 29 in the tank distributer 25is connected to the channel 8 by way of the interface opening 28. Theinterface opening 27 can also be created by a continuous bore in thebase member 3 which is closed by a stopper 30.

The tank module 25 likewise comprises a stack of plates 31, 32, theplate 31 being formed with grooves which become channels 29, 33, 34 whencovered by the plate 32.

The tank module 25 has at its upper end a mounting 35 and at least oneconnection, three connections 36, 37, 38 in the embodiment illustrated,for fluid tanks. Three tanks having different fluid levels areillustrated inserted in the mounting 35. The mounting 35 can also beplaced immediately adjacent to the tank module 25. The offset was chosenin this particular illustration in order to be able to show theconnections 36, 37, 38. The mounting 35 can also itself be constructedas a tank and receive fluids directly.

The connections 36, 37, 38 are preferably constructed as quick-releaselocks. They can have an upwardly pointing needle or another piercingdevice so that basically the respective tank merely needs to be insertedfrom above into the mounting 35. The needle pierces its opening and thefluid contained therein is able to flow out downwards.

At the lower end of the base member 3, arranged in a similar way to thetank module 25, is an evaluation module 39, which lies adjacent to thebase member 3 by way of a further interface 40. Again, in the interface40 there is an interface opening 41 which is in the form of athrough-bore and is closed by stopper 42. Through this interface opening41 fluid is able to flow from the channel 9 into the evaluation module39. The evaluation module 39 is also constructed from two plates 43, 44;grooves provided in plate 43 form channels 45 when covered by the otherplate 44.

As can be seen in FIG. 1, a detector module comprising an opticaldetector 47, 48 with a measuring path 49 is positioned externally on theevaluation module 39. Because the detector module 46 is likewisepositioned from the outside on the evaluation module 39, the detector isreadily exchangeable.

Furthermore, a pump 50 which is able to draw a sample fluid by way of asample-removal channel 51 from a connection 52 is arranged on theevaluation module 39. The manner in which the sample is obtained isknown per se, and is not therefore described further.

Finally, a mixing point 53 into which the channel 45 opens is providedin the evaluation module 39, and is moreover charged with fluid from thepump 50.

A reaction channel 54 is arranged between the mixing point 53 and theinput to the detector module 46. This reaction channel is illustratedinside the evaluation module 39. The reaction channel can alternativelybe taken out of the evaluation module 39 and housed in a separatecomponent, which in turn is positioned on the evaluation module 39.

Such an analysis apparatus can operate, for example, according to theprinciple of the flow-injection analysis system (FIA). Here, using oneof the pumps a flow is produced from the tank module through the channel45, the mixing point 53, the detector module 46 and the channel 19having the pump 24 back to a different tank. At intervals the pump 50feeds a defined sample amount into the mixing point 53 and the resultingreaction of the sample with the continuously flowing reagent fluid isdetermined in the detector module 46.

The analysis apparatus preferably operates, however, as a continuousflow analysis system (CFA). In that case there is a small flow ofreagent fluid. The pump 50 draws a defined amount of sample fluid fromthe connection 52 and conveys this amount to the mixing point 53. At thesame time reagent from connection 36 is conveyed to the mixing point 53,for example, by way of the pump 12. At the mixing point the sample fluidconveyed by the pump 50 reacts with the reagent fluid and the mixture ispassed through the channel 54 into the detector module 46. The detectormodule evaluates, for example, changes in colour. The pump 24 then pumpsthe fluid out of the detector module 46 into a waste tank, for example,by way of the connection 38.

As is shown particularly in FIG. 1, the main flow direction of thefluids in the member 3 is primarily from top to bottom and from bottomto top, whilst the main movement direction of the fluid in the tankmodule 25 is from left to right and from right to left. Through the useof different modules it is therefore possible to ensure that thechannels run substantially in straight lines. Intersections are largelyavoided within a module. This produces clearly defined flow conditions,which are particularly desirable in an analysis according to the CFAsystem.

As can be seen, a different configuration of the individual channels canbe achieved relatively quickly by exchanging the tank module 25. Becausethey are arranged on the outside of the base member, the pumps can bequickly exchanged, which is advantageous firstly for maintenance andsecondly also at an experimental stage when one is not yet certain whatpump or what pump size is correct.

What is claimed is:
 1. An analysis for carrying out chemical analyses,comprising a base member having at least one channel, at least onefunctional element being in fluid or gaseous connection with thechannel, the functional element being positioned on an exterior surfaceof the base member being in connection with the channel by means of atleast one interface opening, the base member comprising a stack ofplates with at least two adjacent plates having a contact area, thechannel being formed in the contact area, at least one plate comprisinga mounting plate and having a mounting area for the functional element,the base member having at least one pump module mounted thereon as asaid functional element, at least one tank module and one evaluationmodule being connected with the pump module, the modules bearing on theexterior surface of the mounting plate with interface surfaces, and eachmodule having a main flow direction, the main flow direction of at leasttwo modules differing from each other.
 2. An apparatus according toclaim 1, in which the pump module includes at least one valve.
 3. Anapparatus according to claim 1, in which the pump module includes aplurality of pumps which are arranged in several rows the pumps in eachrow being offset with respect to the pumps in each adjacent row.
 4. Anapparatus according to claim 1, in which the tank module has a tankmounting and a connection for at least one tank.
 5. An apparatusaccording to claim 4, in which the connection comprises a quick-releasecoupling and having a tank-piercing device.
 6. An apparatus according toclaim 1, in which the evaluation module includes at least one detectorwhich is located in a detector module.
 7. An apparatus according toclaim 6, in which the evaluation module includes a sample-removalchannel.
 8. An apparatus according to claim 7, in which the evaluationmodule has a mixing point which is connected to the sample-removalchannel.